Emitters have a wide range of potential applicability in the microelectronics field. An emitter emits electrons in response to an electrical signal. The controlled emissions form a basis to create a range of useful electrical and optical effects. Emitters include spindt tip cold cathode devices as well as flat emitters.
Challenges presented by spindt tip emitters include their manufacturability and stability over their service life. Manufacturing of spindt tip emitters requires a number of relatively difficult deposition steps, with the result that it is generally expensive and time consuming. Once formed, a tip may be unstable as it can change as it is operated, and is subject to damage if not operated in high vacuum.
Flat emitters are advantageous compared to spindt tip emitters because they present a larger emission surface and can be operated in less stringent vacuum environments. Flat emitters include a dielectric emission layer that responds to an electrical field created by a potential applied between an electron source and a thin metal layer on either side of a dielectric layer. Electrons tunnel from the valence band to the conduction band of the dielectric. Once into the conduction band, the electrons are accelerated towards the thin metal layer. The electrons then travel through the thin metal and exit the emitter. While flat emitters have advantages relative to spindt tip emitters, they are less efficient. It would be advantageous to improve the efficiency of flat emitters.